1. Field of the Invention
The present invention relates generally to a seat belt system for restraining an occupant of a vehicle and, more particularly, to a D-ring used to attach the shoulder portion of a seat belt in an automobile body assembly.
2. Description of Related Art
One type of seat belt system connects at three places to the vehicle body and incorporates both a lap belt section and a shoulder belt section to restrain movement of an occupant should sudden vehicle deceleration occur, for example a collision. The seat belt extends upward from a seat belt retractor, typically anchored to the vehicle body, to and through a D-ring, anchored to the vehicle body. The seat belt extends across the occupant's body and with a tongue received in a buckle securing the seatbelt in place.
Various types of seat belt retractors are commonly used. One type of seat belt retractor includes a spool or reel including a torsion spring used to wind up and store the webbing of a seat belt. Some retractors use a motor that operates to wind and unwind the seat belt. As the seat belt is withdrawn or unwound from the spool or reel, it passes over the D-ring. Upon retraction, the seatbelt moves again over the D-ring in the opposite direction.
The seat belt retractor provides sufficient force to retract the seat belt through the D-ring until it reaches a fully withdrawn position. To fasten the seat belt, the vehicle occupant exerts a force that overcomes the retraction force whereby the occupant can withdraw or pull the seat belt out of the seat belt retractor, over the D-ring, across the occupant's body and place the tongue in the buckle. Once buckled the seat belt retractor exerts a certain retraction force to remove any slack from the seat belt, which depending upon the severity of the retraction force, may cause a feeling of confinement.
Reducing the retraction force needed to pull the seat belt back into the seat belt retractor and wind the seat belt around the spool reduces the pressure felt by the vehicle occupant during use.